Usually the sow will soon estrus after weaning, and the estrus appears on average 7 days after weaning, the first is 2 days, and the latest is 17 days. The sow is postponed or not estrus after weaning. It is also called the sow after weaning. It means that the sow cannot be naturally estrus within 20 days after weaning, and even if it has not appeared for more than 30 days, the sow has not been used for a long time. There is another estrus. This is a common reproductive disorder problem in the current lean meat variety and its binary hybridization, and it is more prominent in large-scale pig farms.
1. Analysis of the reasons for delaying estrus or estrus after weaning.
There are many reasons for delaying estrus or estrus after sow weaning. The main factors are the following:
1. The age of young sows is too early: young sows who have just entered the puberty stage, although their genitals have normal reproductive function, do not mean that they can be formally mated at this time. Because young sows prematurely breed and conceive, it will not only lead to less primiparous birthlets, but also have small birth weight, small weaning and low survival rate, and will also affect the weight gain of the sow itself. Less than the same breed of sows (usually small light 25-40 kg). This sow, which is underweight, has a significant delay in estrus after weaning, and some even do not estrus for a long time.
2. Sows lose too much weight when weaning: Under normal circumstances, the sows undergo a lactation period, and their body weights are reduced to varying degrees. The proportion of general weight loss is about 25%, which does not affect the normal estrus after weaning. Breeding, however, if the diet is nutrient-deficient, the amount of milk is large, and there are too many litters. When the sow is weaned, it will be abnormally thin, and the weight loss will be too large. If it exceeds 60 kg, the breeding of the sows after weaning will be significantly delayed.
3, the seasonal impact: sows are multi-cycle estrus livestock, can be continually estrus breeding. However, in the hot summer season (June-September), 7 days after piglet weaning, the sow estrus rate is 20% lower than other seasons, especially for primiparous sows, and 25% lower than for sows. Lean meat varieties and their binary hybrid sows are more sensitive to high temperatures. Summer temperatures above 29.4 °C will interfere with the performance of sows' estrus behavior, reduce feed intake and ovulation counts, and maintain high temperatures above 32 °C in summer. Many sows stop estrus.
4. Sows are over-fertilized: some sows are lactating, have low lactation, and have fewer piglets; there are also pig farms fed with high-protein and high-energy diets, which are kept for a long time, until the weight is not reduced during weaning, and the body is deposited. A lot of fat, causing the body to be too obese, causing the sow follicle development to stop and not normal natural estrus breeding.
5, the materials are unscientific: some pig farms do not use sow-specific feed, but use the growth and fattening pig feed to raise sows, although the cost of feeding is lower, but the longer feeding time may bring great harm.
6, endocrine abnormalities: sows during birth, birth canal damage, pollution, fetal dressing or fetal and debris remaining, uterine flaccidity when the lochia stays, dystocia surgery is not clean, artificial insemination is not thorough disinfection, breeding boar genital or semen Contains inflammatory secretions; or sows with inflammation caused by brucellosis or other microbial infections in the reproductive system of the sow. These disease factors can cause the sow to delay or not estrus.
Second, the treatment of delayed estrus or estrus after the sow is weaned.
1. Correctly master the initial maturity of young sows: It has been proved that the domestic cultivated varieties and their hybrid young sows are not more than 8 months old and have a body weight of not less than 100 kg. The experienced pig farm is to let the "three sexes", that is, let three estrus periods, generally one estrus cycle is 18-21 days, so about 2 months after the puberty period, the youth will be the fourth estrus The gilts are put into breeding and breeding.
2, the use of "low pregnancy, high lactation" feeding method: the correct feeding method for sows should be "low pregnancy, high lactation", that is, the sow should be allowed to maximize the body condition during lactation, sow weaning The weight loss will not be too much. A consistently enhanced feeding method is adopted for lactating sows with a thin body condition. Lean meat type and binary hybrid sows feed 4-5 kg ​​per day (feeding 8 piglets), feeding 10-12 piglets, feeding 5-6 kg per day, so that the whole lactating sow The weight loss is controlled within 60 kg as the normal feed rate standard. Choose the full-price material for lactating sows and feed it 3-4 times a day.
3. Drip cooling: As long as the temperature rises above 33 °C, the body of the empty sow can be sprayed once at 11 am and 3 pm, 6 pm and 9 pm. However, when the humidity of the air is too high, it is necessary to use a water spray to cool down with good ventilation. A special drip cooling device can be designed for lactating sows. According to reports, the daily feed intake of sows that use dripping water is more than 0.95 kg, and the sows in the whole lactation period lose 13.7 kg.
4. Restricted materials: In some pig farms, the sows have a high level of feeding during lactation. Under the condition of 28 days of weaning, the sows have little weight loss during lactation, and the sensation is too fat, which often affects the estrus breeding of the sows. The method of eating or adding 5%-10% green fodder to the sow diet increases the amount of sow movement and sun exposure, making the sow less obese. In recent years, some pig farms have adopted hunger stimulation measures to change the living conditions of sows. The sows are not fed for 1-2 days after weaning, or the amount of daily feeding is very small, but water shortage is not allowed. The sows estrus quickly after hunger stimulation and return to normal rearing immediately after mating.
5. Select the full-price material for the sow : the full-price material for the sow is carefully prepared according to the different physiological stages of the sow. The nutrient content of the diet is completely in line with the physiological needs of the sow and will not cause the reproductive performance of the sow. influences.
6, hormone aphrodisiac: For estrus, the following hormones can be used for aphrodisiac.
1 intramuscular injection of diethylstilbestrol 3-10 mg, or pituitary anterior pituitary gonadotropin 1000 units (500 units each time, interval 4-6 hours, in the first 1-2 days before the prediction of the next estrus period. But pay attention to the record , timely breeding.
2 intramuscular injection of 3 ml of triad hormone, or 4 mg of diethylstilbestrol, or prostalenol 1 · 2 - 2 · 0 ml for sows without estrus, after 4 days, the same dose of intramuscular injection. The sows that were treated after estrus were intramuscularly injected with 1000 units of chorionic gonadotropin 8-12 hours before breeding.
3 cloprostenol can effectively dissolve the persistent corpus luteum on the ovary of gilts that do not show estrus, so that the sows have normal estrus, and each sow is intramuscularly injected with 2 ml (0.2 mg).
4 muscle injection of 2 ml of placenta, 4 oxytocin.
7, prevention and treatment of primary disease
Adhere to the prevention and treatment of diseases such as Japanese encephalitis, swine fever, parvovirus, Brucella, toxoplasma; timely treatment for sows with genital diseases; no moldy feed; mother with metritis Pig, first treatment, use 2% - 4% baking soda solution 400 ml or 1% potassium permanganate 20 ml or 50 ml distilled water + 6.4 million toxins + 3.2 million streptomycin, catheter input rinse, remove exudate, 2 times a day for 3 consecutive days. At the same time, the muscle injection of fetal poisoning 2 ml, pregnant horse serum 10 ml, vitamin E 2, vitamin A 2, promote estrus ovulation.
8. Those who are poorly managed and managed
Take the "one teasing, two squatting, three changing circles, four treatments" approach. A tease: use the test boar to chase long-lost sows (15-20 minutes once, for 3-4 consecutive days), or drive the sows in the same circle, stimulate through the boar's climbing, etc. The sow's pituitary gland produces follicles and promotes estrus ovulation. Second é›: Every morning, the sows are driven out of the circle for 1-2 hours to accelerate blood circulation and promote estrus. Three-ring change: The sows that have not been estrus for a long time are transferred to the sow circle that is in estrus, and the stimulating sows are stimulated to stimulate ovulation. Generally, 4-5 shows obvious estrus. Four treatments:
1 Chorionic gonadotropin (HCG): 500-1000 international units for one intramuscular injection. If the HCG300-500 unit is mixed with the pregnant horse serum (PMS) 10-15 ml, the intramuscular injection is not only effective, but also can improve the production. The number of children is 0·6—0·9.
2 drink brown sugar water: For the sows that are not estrus or postpartum, take 250-500 grams of brown sugar according to the weight of the body, heat the coke in the pot, add the appropriate amount of water to boil the mixture, and feed for 2-7 days. The sows can estrus 2-8 days after eating and receive breeding.
3 boar semen: After the boar semen is diluted 1:3, take 1-3 ml spray on the nose or nostrils of the sow, express estrus after 4-8 hours, peak in estrus in 12 hours, and breed in 16-18 hours. Best, the conception rate is 95%.
4 boar urine: boar urine contains pheromone, can stimulate the pituitary gland to produce gonadotropin, promote follicle maturation and ovulation. The insemination causes the sow to smell the boar urine for 2-3 minutes, and then insert the vas deferens into the vagina. After twitching and stimulating the vaginal wall and the cervix for 2-3 minutes, the semen is injected. Results The conception rate increased by 16.7%, and the average litter size was more than 21.11.
5 feeding the uterus and ovaries: 2-3 pairs of uterus and ovaries of the castrated sows, even feeding the sows for 2-3 days, estrus occurs after 4-5 days.
6 electro-acupuncture stimulation: use electro-acupuncture to stimulate the sow Baihui point, cross nest for 20-25 minutes, once every other day, twice.
7 Chinese herbal medicine aphrodisiac: Epimedium, 80 grams of leaf grass, Jianshui oral administration; Epimedium 100 grams, 80 grams of Salvia, 50 grams of safflower and angelica, mixed with the milled material.
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